Water Systems for Small Communities

A Puzzle Guide for Local Officials
Bulletin 910

Monitoring Drinking Water Sources

Jeff Morrison, Assistant Director, Operator Training Committee of Ohio
Karen Mancl, Professor Food, Agricultural and Biological Engineering, The Ohio State University

Monitoring a drinking water source is one tool an operator uses to improve the efficiency of a system. Source water monitoring is done in four situations:

1. Early warning of contamination or changes in water quality is gained through periodically monitoring a water source. The frequency of this type of monitoring ranges from daily for a surface water source to monthly for groundwater. With monitoring information, a water system operator can make adjustments in their operation to minimize the impact of contamination on the water system. Actions that could be taken include making a shift in a water source to let contamination diminish, blending water sources appropriately, or adjusting treatment procedures to minimize costs while providing safe water to customers.
2. Changes in water chemistry occur quickly in surface water sources with weather and runoff. Water temperature, pH, and turbidity all affect water treatment processes and need to be monitored. Some water systems soften water for customers and need to monitor hardness and alkalinity to make necessary adjustments in treatment procedures.
3. Contaminants present in a water source at even threshold levels may require monitoring. While not an immediate health threat, increases in these contaminants can put them over legal maximum contaminant levels. In these cases, Ohio EPA will specify a monitoring frequency based on the nature of the public health threat.
4. Source designation testing is an issue for new groundwater sources. Regular testing of a well for total coliform bacteria and turbidity is required to prove that a groundwater supply is not influenced by surface water. This testing may be required for a year or more.

Continual evaluation of a water source may indicate a need to develop a different source. The expense of new water source development may be less than the continual testing and treatment of a source with poor water quality. Regular source water testing gives water system managers and operators the information they need to make decisions for the future.